Brace system

ABSTRACT

The present disclosure provides a brace system including an upper portion and a lower portion. The brace system may also include a first pulley rotatably coupling the upper portion to a first intermediate link positioned between the upper portion and the lower portion. The brace system may also include a second pulley rotatably coupling the first intermediate link to a second intermediate link positioned between the upper portion and the lower portion. The brace system may also include a third pulley rotatably coupling the second intermediate link to the lower portion. Further, the brace system may include at least one tension-bearing element substantially encircling each of the first pulley, the second pulley, and the third pulley.

CROSS REFERENCE TO RELATED APPLICATIONS

This U.S. patent application is a continuation of, and claims priorityunder 35 U.S.C. § 120 from, U.S. patent application Ser. No. 14/266,989,filed on May 1, 2014, which is hereby incorporated by reference in itsentirety.

GOVERNMENT RIGHTS

This invention was made with U.S. Government support under Contract No.W911QX-12-C-0085 awarded by DARPA. The Government may have certainrights with regard to the invention.

BACKGROUND

Unless otherwise indicated herein, the materials described in thissection are not prior art to the claims in this application and are notadmitted to be prior art by inclusion in this section.

Many existing braces, such as knee braces, are designed withrehabilitation in mind. Typically, natural knee joint motion isinhibited or constrained in some way.

There is a different need, however, for new knee and other joint braceswhich can be used for other purposes. In one example, a person wearing aheavy backpack might benefit from a knee brace which not only providesstability but also reduces the load on the muscles of the knee,particularly the quadriceps. Indeed, when the knee bends, it would bebeneficial to lower the load carried by the knee by applying an externalextension torque. Energy stored during the bending action can be used tostraighten the knee as well. When the leg swings forward for the nextstep, it would be advantageous if the knee brace applied appropriateflexion torque to help lift the foot, or that the brace operated freely,applying minimal torque to the leg.

Existing braces using one degree of freedom (DOF) hinges may besensitive to alignment of the brace to the knee joint. This can be aproblem for assistive (torque-producing) braces. Mismatch between theinstantaneous center of rotation of the hinge and of the knee causesuncomfortable or dangerous loads on the knee as well as making the bracemigrate down the leg. The mismatch may occur because the one DOF hingesare only an approximation of the motion of the knee and because ofdeflection of the flesh where the brace attaches to the leg.

Other existing braces may require rigid structure spanning between themedial and lateral hinges. This enforces a fixed width and makes thebrace wider than might be necessary since it accommodates the width ofthe knee at the desired maximum flexion position. To avoid a sloppy fitand interference of the braces of the left and right legs, these bracestypically require custom fitting to each user. Still other examplebraces may not allow twisting of the foreleg and can restrict a normalDOF of the leg. Such braces can be awkward to use and increase thelikelihood of chafing and migration of the brace. Therefore, an improvedbrace system may be desirable.

SUMMARY

Example brace systems described herein apply flexion and/or extensiontorque to a joint while allowing the normal motion of the joint. A bracesystem may include a medial brace and a lateral brace. The medial andlateral braces may be substantially similar, although some differencesmay be present to better form to the desired joint. In another example,the brace system may include one of a medial or lateral brace. Anexample brace may include an upper portion, a lower portion, and a hingeassembly. The upper portion and lower portion are configured to attachto the upper and lower limbs of a human or animal joint and arepivotably connected to the hinge assembly. In one example, the hingeassembly may include two or more intermediate links.

The brace system may also include two or more pulleys positioned betweenthe upper portion and the lower portion. The brace system may furtherinclude a tension-bearing element substantially encircling each of thepulleys that may be anchored to the lower portion. In one embodiment,the tension-bearing element may be wrapped around the pulleys in aclockwise direction. In this configuration, the tension-bearing elementmay apply an extension torque to the brace system. In an alternativeconfiguration, the tension-bearing element may be wrapped around thepulleys in a counterclockwise direction. In this configuration, thetension-bearing element may apply a flexion torque to the brace system.In yet another configuration, two tension-bearing elements may bewrapped around the pulleys in opposite directions. A firsttension-bearing element may be wrapped around the pulleys in a clockwisedirection to apply an extension torque, and a second tension-bearingelement may be wrapped around the pulleys in a counterclockwisedirection to apply a flexion torque. Other embodiments are possible aswell.

In one embodiment, the present disclosure provides a brace systemincluding an upper portion and a lower portion. The brace system mayalso include a first pulley rotatably coupling the upper portion to afirst intermediate link positioned between the upper portion and thelower portion. The brace system may also include a second pulleyrotatably coupling the first intermediate link to a second intermediatelink positioned between the upper portion and the lower portion. Thebrace system may also include a third pulley rotatably coupling thesecond intermediate link to the lower portion. Further, the brace systemmay include at least one tension-bearing element substantiallyencircling each of the first pulley, the second pulley, and the thirdpulley.

In another embodiment, the present disclosure provides a brace systemincluding an upper portion and a lower portion. The brace system mayalso include a first pulley rotatably coupling the upper portion to anintermediate link positioned between the upper portion and the lowerportion. The brace system may also include a second pulley rotatablycoupling the intermediate link to the lower portion. Further, the bracesystem may include at least one tension-bearing element substantiallyencircling each of the first pulley and the second pulley.

In yet another embodiment, the present disclosure provides a bracesystem including an upper portion and a lower portion. The brace systemmay also include a first pulley rotatably coupling the upper portion toa first intermediate link positioned between the upper portion and thelower portion. The brace system may also include a second pulleyrotatably coupling the first intermediate link to a second intermediatelink positioned between the upper portion and the lower portion. Thebrace system may also include a third pulley rotatably coupling thesecond intermediate link to the lower portion. The brace system mayinclude at least one tension-bearing element substantially encirclingeach of the first pulley, the second pulley, and the third pulley.Further, the brace system may also include an actuator system coupled tothe at least one tension-bearing element, wherein the actuator system isconfigured to apply a torque to the brace system.

These as well as other aspects, advantages, and alternatives will becomeapparent to those of ordinary skill in the art by reading the followingdetailed description, with reference where appropriate to theaccompanying drawings.

DESCRIPTION OF DRAWINGS

FIG. 1 is a side view of a brace system according to an exampleembodiment.

FIG. 2 is a side view of a brace system according to another exampleembodiment.

FIG. 3 is a side view of a brace system according to yet another exampleembodiment.

FIG. 4 is a side view of a brace system according to yet another exampleembodiment.

FIG. 5 illustrates a brace system including an actuator system accordingto an example embodiment.

FIG. 6 illustrates a brace system including an actuator system accordingto another example embodiment.

FIG. 7 is an example brace system being worn by a user.

DETAILED DESCRIPTION

Example methods and systems are described herein. It should beunderstood that the words “example,” “exemplary,” and “illustrative” areused herein to mean “serving as an example, instance, or illustration.”Any embodiment or feature described herein as being an “example,” being“exemplary,” or being “illustrative” is not necessarily to be construedas preferred or advantageous over other embodiments or features. Theexample embodiments described herein are not meant to be limiting. Itwill be readily understood that the aspects of the present disclosure,as generally described herein, and illustrated in the figures, can bearranged, substituted, combined, separated, and designed in a widevariety of different configurations, all of which are explicitlycontemplated herein.

Many existing braces are designed with rehabilitation in mind, such thatnatural knee joint motion is inhibited or constrained in some way. Thereis a different need, however, for assistive (torque-producing) braces.For example, a person wearing a heavy backpack might benefit from a kneebrace which not only provides stability but also reduces the load on theknees of the wearer. Example brace systems described herein applyflexion and/or extension torque to a joint while allowing the normalmotion of the joint. In accordance with the described embodiments, aflexion or extension torque is applied to a joint (e.g., knee, ankle,finger joint, or the like) while allowing the normal motion of thejoint. For instance, to assist the knee joint, a torque is applied tothe thigh and an equal and opposite torque is applied to the foreleg.

It should be understood that the above examples are provided forillustrative purposes, and should not be construed as limiting. As such,the method may additionally or alternatively includes other features orincludes fewer features, without departing from the scope of theinvention.

Systems and devices in which example embodiments may be implemented willnow be described in greater detail. FIG. 1 illustrates a side view ofone example brace 100 of an example brace system. The brace system maycomprise a single brace positioned on the desired joint, or may includea medial brace and a lateral brace. The medial and lateral braces aresecurable about a leg, for example, via cross members. The cross-membersmay include fabric with Velcro or other fasteners, plastic sleeve typeconfigurations, or the like. In one example, the cross-members are madeof pliable material (e.g., fabric) so the medial and lateral braces cantaper inwardly to better follow the contours of the knee or other joint.The medial and lateral braces may be substantially similar, althoughsome differences may be present to better form to the desired joint.

As shown in FIG. 1 , each brace may include an upper portion 102, alower portion 104, and a hinge assembly 106. The upper portion 102 andlower portion 104 are configured to attach to the upper and lower limbsof a human or animal joint and are rotatably connected to the hingeassembly 106. The upper portion 102 and lower portion 104 may includecarbon fiber material, plastic, metal, or a combination of materials.The hinge assembly 106 as shown in FIG. 1 may include two or moreintermediate links 108, 110. The use of two or more intermediate linksallows planar/parallel motion of the lower portion 104 relative to theupper portion 102. This makes the brace 100 less sensitive to fore-aftmisalignment. In effect, the hinge assembly 106 can stretch and contractin the longitudinal direction.

The brace 100 may also include a first pulley 112 rotatably coupling theupper portion 102 to the first intermediate link 108, a second pulley114 rotatably coupling the first intermediate link 108 to the secondintermediate link 110, and a third pulley rotatably coupling the secondintermediate link 110 to the lower portion 104. Each of the threepulleys 112, 114, and 116 may be positioned between the upper portion102 and the lower portion 104.

The brace 100 may further include a tension-bearing element 118 thatsubstantially encompasses the pulleys 112, 114, and 116 and may beanchored to the lower portion 104. Each of the pulleys 112, 114, and 116may be coupled to the brace 100 via a pin, or other rotatable membersuch that each of the upper portion 102, the first intermediate link108, the second intermediate link 110, and the lower portion 104 mayrotate independent to one another. The pulleys 112, 114, and 116, andintermediate links 108 and 110 form a parallel-action mechanism whichprovides substantially parallel motion of the lower portion 102 withrespect to the upper portion 104 without extending or retracting thetension-bearing element 118. These two translational DOF arenon-actuated, meaning that they can happen freely (except for friction)even when the tension-bearing element 118 is under load and the brace100 is exerting torques on the limbs adjacent to the joint. The twotranslational DOF make the brace 100 far less sensitive to alignmentwith the body and avoid shear loading of the knee. “Pistoning” forces(along the long axes of the upper portion 102 and lower portion 104) arealso largely avoided, which minimizes the tendency of the brace tomigrate, e.g. shift down the leg while walking. Further, the twotranslational DOF allow the brace 100 to fit individuals of many sizes,thereby reducing the need for a customized brace for each use case. Inaddition, the tension-bearing element 118 substantially encompassing thepulleys 112, 114, and 116 enables the angle between the upper portion102 and the lower portion 104 to extend beyond 180 degrees. Such acapability may be advantageous to measure hyperextension of a joint, asan example. As another example, it may be advantageous for the hingeassembly 106 to be aligned on a user in a way that the hinge assembly106 is hyperextended in a user's resting extension position. In such acase, it would be advantageous to be able to apply torque to the brace100 beyond 180 degrees.

In general, it should be understood that the parallel-action mechanismsdescribed herein do not have to be perfect. Some deviation from parallelmotion may even be desirable, e.g. to make the links of the hingeassembly 106 open in a certain order, or to compensate for friction. Aslong as the hinge action produces approximately parallel motion of thelower portion 104 with respect to the upper portion 102, thetranslational forces applied to the arms of the brace 100 by the hingeassembly 106 will be small, even when the brace is under load.

The pulleys 112, 114, and 116 may have various configurations. In oneexample, the pulleys 112, 114, and 116 may be rotating pulleys thatrotate as the tension-bearing element 118 moves over the pulley. Inanother example, the pulleys 112, 114, and 116 may be fixed pulleys witha low-friction surface configured to enable the tension-bearing element118 to slide over the pulley. The tension-bearing element 118 mayinclude a cable, a cord, a belt or a band, as examples. Thetension-bearing element 118 may be used to apply a torque to the braceor simply to measure the knee angle without ever applying torques, asdiscussed in more detail below. In another example, each of the pulleys112, 114, and 116 may include sprocket teeth 117, and thetension-bearing element 118 may include a chain 119. Other examples arepossible as well.

In another configuration, the brace 100 may only include a singleintermediate link positioned between the upper portion 102 and the lowerportion 104. In such an embodiment, the brace 100 may also include afirst pulley rotatably coupling the upper portion 102 to the singleintermediate link, and a second pulley rotatably coupling the singleintermediate link to the lower portion 104. The single intermediate linkmay be configured with at least one non-actuated degree of freedom inaddition to flexion and extension allowing translation of the upperportion 102 with respect to the lower portion 104. In the knee braceexample, this DOF mitigates vertical misalignment of the brace andminimizes shear loads on the knee, but is less effective for fore/aftmisalignment and the resulting pistoning forces. The brace 100 may alsoinclude at least one tension-bearing element 118 substantiallyencircling each of the first pulley and the second pulley.

In yet another embodiment, the brace 100 may include four or morepulleys. As a specific example, if four pulleys are used, the brace 100may include three intermediate links positioned between the fourpulleys. In such an embodiment, the brace 100 may also include a firstpulley rotatably coupling the upper portion 102 to a first intermediatelink, a second pulley rotatably coupling the first intermediate link toa second intermediate link, a third pulley rotatably coupling the secondintermediate link to a third intermediate link, and a fourth pulleyrotatably coupling the third intermediate link to the lower portion 104.The brace 100 may also include at least one tension-bearing element 118substantially encircling each of the first pulley, the second pulley,the third pulley and the fourth pulley. Other numbers of pulleys arepossible as well. For a brace having n pulleys, the brace may includen−1 intermediate links positioned between the n pulleys, and atension-bearing element substantially encircling each of the n pulleys.

In the example shown in FIG. 1 , the tension-bearing element 118 iswrapped around the pulleys 112, 114, and 116 in a clockwise direction.The tension-bearing element 118 completes a full rotation around each ofthe pulleys 112, 114, and 116. However, it is possible for thetension-bearing element 118 to be slightly less than a full rotationaround each of the pulleys 112, 114, and 116. In another example, thetension-bearing element 118 may be wrapped around the pulleys 112, 114,and 116 a number of times. In the configuration shown in FIG. 1 , astension is applied to the tension-bearing element 118, the angle betweenthe upper portion 102 and the lower portion 104 increases, therebyapplying an extension torque to the brace 100. In addition to applyingan extension torque, the tension-bearing element 118 may be coupled to ameasurement system configured to measure the angle of the joint. Themeasurement system may be in communication with a processor on acomputing device, which may in turn process the joint angle data andapply an extension torque in response to the joint angle data. Forexample, the measurement system may convey joint data information to theprocessor that the knee joint is fully flexed, and the processor maythen instruct the brace 100 to apply an extension torque to straightenthe knee joint.

The measurement system may use the tension-bearing element 118 tomeasure the angle of the joint by a change in length across the hingeassembly 106. In particular, the measurement system may measure themotion of the tension-bearing element 118 on the non-anchored side ofthe brace 100. The measurement system may determine a joint angle basedon the measured motion of the tension-bearing element 118. In anotherexample, the measurement system may be configured to measure the changein length of the tension-bearing element 118 or another non-tensionbearing element across one or more of the pulleys 112, 114, 118. In yetanother example, the measurement system may be configured to measure thechange in rotation of one or more of the pulleys 112, 114, 118. Otherexamples are possible as well.

FIG. 2 illustrates an alternative configuration, in which thetension-bearing element 120 is wrapped around the pulleys 112, 114, and116 in a counterclockwise direction. Similar to the tension-bearingelement 118 illustrated in FIG. 1 , the tension-bearing element 120 inFIG. 2 completes a full rotation around each of the pulleys 112, 114,and 116. However, it is possible for the tension-bearing element 120 tobe slightly less than a full rotation around each of the pulleys 112,114, and 116. In another example, the tension-bearing element 120 may bewrapped around the pulleys 112, 114, and 116 a number of times. In theconfiguration shown in FIG. 2 , as tension is applied to thetension-bearing element 120, the angle between the upper portion 102 andthe lower portion 104 decreases, thereby applying a flexion torque tothe brace 100. In addition to applying a flexion torque, thetension-bearing element 120 may be coupled to a measurement systemconfigured to measure the angle of the joint. The measurement system maybe in communication with a processor on a computing device, which may inturn process the joint angle data and apply flexion torque in responseto the joint angle data. For example, the measurement system may conveyjoint data information to the processor that the knee joint is fullyextended, and the processor may then instruct the brace 100 to applyflexion torque to bend the knee joint.

FIG. 3 illustrates an alternative configuration, in which twotension-bearing elements 118, 120 are substantially encircling thepulleys 112, 114, and 116. A first tension-bearing element 118 iswrapped around the outside of pulleys 112, 114, and 116, and a secondtension-bearing element 120 is wrapped around the pulleys 112, 114, and116 in a counterclockwise direction to apply a flexion torque to thebrace system 100. The first tension-bearing element 118 may be coupledto a measurement system to measure the angle of the joint, as discussedabove. In another embodiment, the first tension-bearing element may bewrapped around the pulleys 112, 114, and 116 in a clockwise direction toapply an extension torque to the brace system 100, and the secondtension-bearing element 120 may be wrapped around the outside of pulleys112, 114, and 116 and may be coupled to a measurement system to measurethe angle of the joint.

FIG. 4 illustrates another alternative configuration, in which the twotension-bearing elements 118, 120 are wrapped around the pulleys 112,114, and 116. A first tension-bearing element 118 is wrapped around thepulleys 112, 114, and 116 in a clockwise direction to apply an extensiontorque to the brace system 100, and a second tension-bearing element 120is wrapped around the pulleys 112, 114, and 116 in a counterclockwisedirection to apply a flexion torque to the brace system 100. The pulleys112, 114, and 116 may include a separate track for each tension-bearingelement so that the first tension-bearing element 118 and the secondtension-bearing element 120 do not tangle. In another example, each ofthe pulleys 112, 114, and 116 may include multiple separate pulleys eachsharing a common axis of rotation. Other embodiments are possible aswell.

The first tension-bearing element 118 and the second tension-bearingelement 120 may be coupled to a measurement system configured to measurethe angle of the joint. The measurement system may be in communicationwith a processor on a computing device, which may in turn process thejoint angle data and apply a torque in response to the joint angle data.In one example, the brace 100 may use the second tension-bearing element120 to measure the joint angle when the brace 100 is applying anextension torque using the first tension-bearing element 118. Similarly,the brace 100 may use the first tension-bearing element 118 to measurethe joint angle when the brace 100 is applying a flexion torque usingthe second tension-bearing element 120.

In another embodiment, additional tension-bearing elements may be placedover the pulleys 112, 114, and 116 and coupled to a measurement systemto measure the angle of the joint. For example, one set oftension-bearing elements may be wrapped around the pulleys 112, 114, and116 to apply extension and/or flexion torques to the brace 100, and asecond set of tension-bearing elements may be wrapped around the pulleys112, 114, and 116 to measure the joint angle. Other embodiments arepossible as well.

FIG. 5 illustrates a brace system 100 including a medial brace 100 a anda lateral brace 100 b. As shown in FIG. 5 , the each of the medial brace100 a and the lateral brace 100 b may include all of the featuresdescribed in FIG. 1 . Further, the medial brace 100 a is shown having aslightly larger upper section 102 a so as to better conform to theinside of a wearer's thigh. The brace system 100 of FIG. 5 also includestwo actuators 122 a, 122 b according to an example embodiment. In thisexample, there is one tension-bearing element 118 a, 118 b coupled toeach of the actuators 122 a, 122 b. The tension bearing elements 118 a,118 b may be substantially encircling the pulleys 112, 114, and 116 toapply either an extension torque (using the configuration shown in FIG.1 ) or a flexion torque (using the configuration shown in FIG. 2 ) tothe brace system 100. The actuators 122 a, 122 b may be hydraulicactuators, or pneumatic actuators, as examples. Further, the actuators122 a, 122 b may be in fluid communication so that the pressure betweenthe two actuators 122 a, 122 b equalizes, thereby ensuring that the sametorque is applied to each of the medial brace 100 a and lateral brace100 b of the brace system 100. Other example actuator configurations arepossible as well.

FIG. 6 illustrates a brace system 100 including an actuator systemaccording to another example embodiment. In FIG. 6 , the brace systemincludes four actuators 122 a, 124 a, 122 b, and 124 b. Actuator 122 amay be coupled to tension-bearing member 118 a to apply an extensiontorque to the medial brace 100 a of the brace system 100. Actuator 124 amay be coupled to tension-bearing member 120 a to apply flexion torqueto the medial brace 100 a of the brace system 100. Similarly, actuator122 b may be coupled to tension-bearing member 118 b to apply anextension torque to the lateral brace 100 b of the brace system 100, andactuator 124 b may be coupled to tension-bearing member 120 b to applyflexion torque to the lateral brace 100 b of the brace system 100. Theactuators 122, 124 may be hydraulic actuators or pneumatic actuators,among other possibilities as discussed above.

The actuators described above in relation to FIGS. 5 and 6 may becoupled to a hydraulic circuit to assist in various actions. In oneexample, the hydraulic circuit may be intended to assist walking with aheavy pack. In this example, the brace system 100 may include positionsensors and pressure sensors to provide knee position and torque data toa controller (e.g., a microprocessor, FPGA, microcontroller, or thelike). Based on these inputs and knowledge of typical walking gaitcycles, the controller may be programmed to close a valve in theactuator just prior to heel-strike. At heel-strike, the leg bends andforces fluid in the actuators. In effect, the brace acts like a springduring this phase of the gait cycle, called the “weight acceptancephase”. The knee and brace flex, storing energy in the actuator. Laterin stance when the knee extends, pressurized fluid in the actuatorassists the knee extensor muscles. If the knee extends further than itsangle at heel-strike, pressure will drop below that of the actuator andfluid will flow allowing the knee to extend freely. Late in stance, kneeextension velocity goes to zero (as the knee changes direction) and thecontroller may be programmed to open a valve to allow free flow of fluidin the actuator. This allows the leg to freely flex to provide groundclearance during the swing phase of the gait cycle.

Other hydraulic circuits are possible and can be tailored for otherbehaviors, such as walking downhill, stair descent, etc. Circuits mayalso be designed to store energy on descent and use this energy forassisting ascent. Auxiliary power sources such as electric motors orfuel-driven engines can be used to enable sustained climbing, jumpingetc. Other sensors such as foot force sensors, accelerometers,electromyography sensors, nerve implants, brain implants, etc. may beused as inputs to a controller which can modulate the force in actuatorsthus modulating the torque applied by the brace to the wearer.

FIG. 7 illustrates a wearer with two brace systems, each having a medialbrace and a lateral brace. The illustration of FIG. 7 shows a viewpointin which the medial brace is shown on the left leg of the wearer, andthe lateral brace is shown on the right leg of the wearer. However, inthis embodiment each leg has both a medial and lateral brace. Pliablecross members 126 a, 126 b are shown securing the lateral brace to themedial brace in each brace system. The pliable cross members 126 a, 126b may include a Velcro and loop system to secure and tighten the braceon the wearer. In another example, the pliable cross members 126 a, 126b may include buckles, snaps, or any other means for securing the medialand lateral braces. The cross members 126 a, 126 b may be pliable (e.g.,fabric) so the medial and lateral braces can taper inwardly, to betterfollow the contours of the knee or other joint. In addition, crossmembers made of soft materials can be more easily integrated intoclothing or worn under clothing.

Most existing braces do not allow twisting of the foreleg and thusrestrict a normal DOF of the leg. This makes the braces awkward to useand increases the likelihood of chafing and migration of the brace. Theuse of pliable cross members enables the foreleg to twist in normalmotion, thereby preventing chafing and discomfort for the wearer.

Further, the use of pliable cross-members reduces the size and weight ofthe brace and allows for width adjustment using straps. An additionaladvantage is that the hinge assemblies on the medial and lateral sidesdo not have to be parallel (as viewed from the front). The medial andlateral braces may angle inwardly as defined by the plane of the drawingpage. Since people's legs and knees are generally tapered, this allowsthe hinge assemblies to lie closer to the knee which reduces thelikelihood of interference with the brace on the opposite leg. Eachhinge assembly lies in an angled plane as the joint approaches fullextension.

FIGS. 1-7 illustrate an example brace system designed for a human knee.In such an example, the upper portion of the knee brace may beapproximately the size of a human femur, and the lower portion may beapproximately the size of a human tibia/fibula. However, there are manyother possible implementations for the described brace system. In oneexample, the brace system described above in relation to FIG. 1-7 may bedesigned to fit a limb of a horse, or other animal. In such an example,the sizes of the various components may vary depending on the particularuse case, while the interaction between components remains as describedabove. In another example, the brace system may be configured to fit onan elbow joint of a human. In such an example, the upper portion of theknee brace may be approximately the size of a human humerus, and thelower portion may be approximately the size of a human radius/ulna. Sucha brace may be used to assist a wearer in lifting or unloading heavyobjects, along with other potential use cases. Other examples arepossible as well.

In yet another embodiment, the brace system described above in relationto FIGS. 1-7 may be designed for a robotic system. For example, thebrace system may be used for the knee and elbow joints of a humanoidrobot. As another example, the brace system may be used in amanufacturing robotic arm having an upper portion and a lower portion.Other examples are possible as well.

It should be understood that arrangements described herein are forpurposes of example only. As such, those skilled in the art willappreciate that other arrangements and other elements (e.g. machines,interfaces, functions, orders, and groupings of functions, etc.) can beused instead, and some elements may be omitted altogether according tothe desired results. Further, many of the elements that are describedare functional entities that may be implemented as discrete ordistributed components or in conjunction with other components, in anysuitable combination and location, or other structural elementsdescribed as independent structures may be combined.

While various aspects and embodiments have been disclosed herein, otheraspects and embodiments will be apparent to those skilled in the art.The various aspects and embodiments disclosed herein are for purposes ofillustration and are not intended to be limiting, with the true scopebeing indicated by the following claims, along with the full scope ofequivalents to which such claims are entitled. It is also to beunderstood that the terminology used herein is for the purpose ofdescribing particular embodiments only, and is not intended to belimiting.

What is claimed is:
 1. A brace system comprising: an upper portion; alower portion; and a hinge assembly forming a parallel action mechanismfor the lower portion with respect to the upper portion, the parallelaction mechanism comprising at least two pulleys coupling at least oneintermediate link between the upper portion and the lower portion, thehinge assembly comprising an extension tension-bearing elementencircling each of the at least two pulleys, the extensiontension-bearing element having a first end and a second end, the secondend of the extension tension-bearing element anchored to the lowerportion, wherein the upper portion and the lower portion are rotatablycoupled to the hinge assembly.
 2. The brace system of claim 1, whereinthe parallel action mechanism is configured to generate parallel motionof the lower portion with respect to the upper portion without actuationof the extension tension-bearing element, the parallel motioncorresponding to two translational degrees of freedom.
 3. The bracesystem of claim 1, further comprising an actuator system coupled to thefirst end of the extension tension-bearing element and configured toapply a torque to the brace system.
 4. The brace system of claim 1,wherein the brace system includes a medial brace and a lateral bracesecurable via pliable cross members.
 5. The brace system of claim 1,wherein the extension tension-bearing element comprises a cable or acord.
 6. The brace system of claim 1, wherein each of the at least twopulleys comprises sprocket teeth, and wherein the extensiontension-bearing element comprises a chain.
 7. The brace system of claim1, further comprising a flexion tension-bearing element having a firstend and a second end, the extension tension-bearing element encirclingeach of the at least two pulleys in a first direction, the flexiontension-bearing element encircling each of the at least two pulleys in asecond direction different than the first direction.
 8. The brace systemof claim 7, wherein the first end of the extension tension-bearingelement is coupled to a first actuator configured to apply an extensiontorque to the brace system, and wherein the second end of the flexiontension-bearing element is anchored to the lower portion, and the firstend of the flexion tension-bearing element is coupled to a secondactuator, the second actuator configured to apply a flexion torque tothe brace system.
 9. The brace system of claim 1, further comprising ameasurement system coupled to the extension tension-bearing element, themeasurement system configured to determine an angle of a joint on whichthe brace system is positioned by measuring at least one of: a motion ofthe extension tension-bearing element on the upper portion; a change inlength of the extension tension-bearing element across one or more ofthe at least two pulleys; or a change in rotation of one or more of theat least two pulleys.
 10. The brace system of claim 9, wherein themeasurement system is in communication with a processor of a computingdevice, wherein the processor is configured to receive joint angle datafrom the measurement system, and wherein the processor is furtherconfigured to apply a torque to the brace system in response to thereceived joint angle data.
 11. A method of assembling a brace system,the method comprising: receiving an upper portion, a lower portion, ahinge assembly, and an extension tension-bearing element, the hingeassembly forming a parallel action mechanism for the lower portion withrespect to the upper portion, the parallel action mechanism comprisingat least three pulleys coupled to at least two intermediate links, theat least two intermediate links comprising at least a first intermediatelink and a second intermediate link; rotatably coupling a first end ofthe first intermediate link of the hinge assembly to the upper portion;rotatably coupling a first end of the second intermediate link of thehinge assembly to the lower portion, each of the first end of the firstintermediate link and the first end of the second intermediate linkcomprising at least one of the at least three pulleys; and encirclingthe extension tension-bearing element around each of the at least threepulleys in a first direction; and anchoring a first end of the extensiontension-bearing element to the lower portion.
 12. The method of claim11, wherein the parallel action mechanism is configured to generateparallel motion of the lower portion with respect to the upper portionwithout actuation of the tension-bearing element, the parallel motioncorresponding to two translational degrees of freedom.
 13. The method ofclaim 11, further comprising coupling an actuator system to a second endof the extension tension-bearing element, the actuator system configuredto apply a torque to the brace system.
 14. The method of claim 11,further comprising securing the brace system to another brace systemusing pliable cross members, the brace system and the other brace systemcorresponding to medial and lateral braces configured to support ajoint.
 15. The method of claim 11, wherein the extension tension-bearingelement comprises a cable or a cord.
 16. The method of claim 11, whereineach of the at least three pulleys comprise sprocket teeth, and whereinthe extension tension-bearing element comprises a chain.
 17. The methodof claim 11, further comprising: encircling a flexion tension-bearingelement around each of the at least three pulleys in a second directionopposite the first direction of the extension tension-bearing element,the flexion tension-bearing element having a first end and a second end;and anchoring a first end of the tension-bearing element to the lowerportion.
 18. The method of claim 17, further comprising coupling asecond end of the extension tension-bearing element to a first actuatorand a second end of the flexion tension-bearing element to a secondactuator, the first actuator configured to apply an extension torque tothe brace system, the second actuator configured to apply a flexiontorque to the brace system.
 19. The method of claim 11, furthercomprising coupling a measurement system to the extensiontension-bearing element, the measurement system configured to determinean angle of a joint on which the brace system is positioned by measuringat least one of: a motion of the extension tension-bearing element onthe upper portion; a change in length of the extension tension-bearingelement across one or more of the at least three pulleys; or a change inrotation of one or more of the at least three pulleys.
 20. The method ofclaim 19, wherein the measurement system is in communication with aprocessor on a computing device, wherein the processor is configured toreceive joint angle data from the measurement system, and wherein theprocessor is further configured to apply a torque to the brace system inresponse to the received joint angle data.